Method of and apparatus for producing rods and the like of comminuted material



Nov. 2, 1937.

G. T. SOUTHGATE METHOD OF AND APPARATUS FOR PRODUCING RODS AND THE LIKEOF COMMINUTED MATERIAL Filed March 18, 1935 INVENTOR GEO/P66 7."500777634 7'5.

MTTORNEY 4 Sheets-Sheet 2 INVENTOR ATTORNEY G. T. SOUTHGATE Filed March18, 1933 650%: Z Sour/16,4 r5

Nov. 2, 1937.

METHOD OF AND APPARATUS FOR PRODUCING RODS AND THE LIKE OF COMMINUTEDMATERIAL Nov. 2, 1937. T SQUTHGATE 2,097,502

METHOD OF AND APPARATUS FOR PRODUCING RODS AND THE LIKE OF COMMINUTEDMATERIAL Filed March 18, 1933 4 Sheets-Sheet .3

ATTORNEY .Nov. 2, 1937. G T, SOUTHGATE 2,097,502

METHOD OF AND APPARATUS FOR PRODUCING-RODS AND THE LIKE OF COMMINUTEDMATERIAL Filed March 18, 1933 4 Sheets-Sheet 4 //8 NON-0XIDIZING IN VENTO R 6:0? 7." 5007/1674 TE ATTORNEY Patented Nov. 2, 1937 METHOD OFAND APPARATUS FOR PRO- DUCING RODS AND THE LIKE OF COM- MINUTED MATERIALGeorge T. Southgate, Forest Hills, N. Y., assignor, by mesneassignments, to Union Carbide and Carbon Corporation, a corporation ofNew York Application March 18, 1933, Serial No. 661,493

22 Claims.

This invention relates to a method of and apparatus for producing solidand hollow rods and Wires and the like of comminuted or powderedmaterial. More particularly this invention relates to a method of andapparatus for producing such articles by compacting the material in adie, and extruding the compacted material continuously therefrom. As arod is being extruded from a die, it may be progressively heated toincrease the cohesion or bonding of the powdered material through theagency of sintering, semi-fusion or fusion.

Although not limited thereto, this invention is applicable to theproduction of alloys of substantially uniform composition from thepowders of metals; the formation, from powders,- of alloys and mixturesof metals that ordinarily combine with great difliculty, such as copperand tungsten, which have large difierences in their melting points; theproduction of rods or wires from the powders of refractory metals, suchas tungsten; the production of rods that are mixtures of metals andnon-metals, such as copper and graphite; and the production of bearingsand bushings from powders of suitable materials, such as a mixture ofgraphite, copper and tin.

In this invention the comminuted or powdered material is preferably fedcontinuously into a die in such a manner that predetermined quantitlesor slugs thereof are successively or intermittently impacted by means ofa plunger. As the material is advanced in the die by the plunger, thefrictional resistance of the die causes the material to be compacted toa dense homogeneous mass which is extruded from the die in the form of arod. The rod may then be progressively heated after extrusion from thedie, as stated abnve, s0 as to provide a simple, continuous andeconomical method of producing the finished article.

In order to provide means whereby a rod could be formed in-the mannerabove described, difficulty was experienced in using solid dies becauseof the tendency of the compacted material to jam in the die openingafter the die had been in operation only for a short time. Thisdifilculty was probably due to the fact that no radial relief wasobtained in the die opening to insure the compacted material extrudingfrom the die.

I have found that the above difficulties canbe overcome by using a splitdie, the respective elements of which are resiliently held togetherunder high pressure and provided with aligned and cooperatinglongitudinal grooves at their contacting faces to form the die opening.By this construction. when the frictional resistance of the die openingbecomes very great and the longitudinal movement of the compactedmaterial tends to be retarded, the elements of the die will separate soas to relieve the radial pressure of the compacted material on the wallsof the die opening. The separation of the split die is very slight, butnevertheless suflicient to separate the walls of the die, so thatsufiicient radial relief in the die opening is obtained to insure theextrusion of the compacted material from the die, without any jamming ofthe material during continuous use of the die, to produce a rod as abovedescribed.

One object of my invention," therefore, is to provide an improvedapparatus for continuously producing solid and hollow rods and the likeof comminuted or powdered material. k

Another object of my invention is to produce solid and hollow rods ofcomminuted or powdered material by .compacting the material andextruding the same substantially continuously from a split die, therespective elements of which are resiliently held together under highpressure.

A further object of my invention is to produce solid and hollow rods andthe like of comminuted material, which may include comminuted metal, bycompacting the material in a die and extruding the same therefromcontinuously, and progressively heating successive portions of the rodafter they are formed.

A further object of my invention is to heat progressively to a fusingtemperature successive portions of a rod of compacted comminutedmaterial, and subsequently to cool such fused portions to cause definitestructural changes in the rod material.

A further object of my invention is to provide means for substantiallyuniformly heating successive portions of a rod of compacted comminutedmaterial as they are continuously extruded from a. die.

The above and further objects of my invention will become apparent fromthe following description and accompanying drawings, in which Fig. 1 isa side view, partly in section, of an apparatus embodying the principlesof this invention;

Fig. 2 is an enlarged fragmentary sectional view of certain parts ofFig. 1;

Fig. 3 is a plan view illustrating details of the electrical contactshown in Fig. 1 for passing a current through a rod;

Fig. 4' is a sectional view taken on line 4-4 0 Fig. 1;

Fig. 5 is a view taken on line 5- -5 of Fig. 4;

Fig. 6 diagrammatically illustrates a control system that may be appliedto the apparatus I portion of the apparatus shown in Fig. "I;

Fig. 9 is an enlarged sectional view to show more clearly detailsillustrated in Fig. I; and

Fig. 10 is a side view, partly in section, of a further modification ofthe apparatus illustrated in Fig. 1.

Referring to Fig. 1, the apparatus illustrated as embodying theprinciples of this invention comprises a driving motor M having a shaft||l and mounted on a base plate The shaft III is connected by a couplingH to a shaft l2 which drives, through suitable reduction gearing, ashaft l4. The reduction gearing is enclosed in a housing I 5 mounted onthe base plate I I, and the shaft i4 is journaled in an opening, in thewall of the housing 'and an opening in a bracket II which is fixed to aframe plate II. The frame I! is preferably straight and is mounted onthe base plate II at an acute angleto the horizontal base II, and isprovided with one or more brace members l8, the endsof which are securedto the frame I! and base plate M, respectively.

The rotary motion of the shaft I4 is converted into rectilinearreciprocatory motion by a connecting rod l9, one end of which is mountedon an eccentric 20 fixedly secured at 2| to the shaft I4. The oppositeend of the connecting rod I9 is pivotally connected at 22 to a thrustrod 22, which reciprocates in a guide block 24 that is mounted on theframe ll.

This rectilinear reciprocatory motion is imparted to a plunger 25 byconnecting the outer end thereof in the socket 26 at the end of thethrust rod 23. The plunger 25 is received in an opening 21 of a die D,which is mounted on the frame l1, so that the die opening 21 is at anacute angle to a vertical line perpendicular to the horizontal baseplate I I. The impacting end 28 of the plunger 25 is preferably reducedand tapered to insure a strong joint between successive quantities ofpowdered material as they are compacted and compressed together by theplunger 25, to form a solid rod 29. V

In accordance with this invention, the die D is preferably a split die,the respective die elements of which are resiliently held together underhigh pressure. Referring more particularly to Figs. 4 and 5, the die Dpreferably comprises a housing 30 having? an opening 31 in which arepositioned cooperating die elements 3| and 22 provided with cooperatinglongitudinal grooves that form the die opening 21. The grooves of thedie elements 3| and 32 may be nitrided or lined with a metal having ahigh degree of hardness, such as an alloy composed of cobalt, chromiumand tungsten, as indicated at 82 and 24, so that the die elements willwithstand wear and the high temperatures which result from continuousoperation of the apparatus. The metallic linings may be formed in thedie elements in any suitable. manner, such as by electroplating or bywelding. The die elements 2| and 22 may also be provided withlongitudinal openings 25 and 36, through which a cooling medium such aswater may be circulated in any suitable manner for dissipating the heatproduced by the compacting and compressing of powdered material to forma rod thereof, and for dissipating the heat conducted to the dieelements as a result of the,

heating of the rod, hereinafter to be described. In order to maintainthe die opening 21 in alignment with the plunger 25 and theparts of theapparatus to be described, the die elements 2| and 22 are preferablypositioned at one side within the opening 31 of the housing 20, with thedie element 2| abutting the inside face of the end wall 24. Longitudinalmovement of the dieelernents II and 22 within the housing 30 isprevented by guide pins 29 which extendthrough openingsin the end wall38 and transverse openings 4| and 42 in the die elements 3| and 32. theheads 43 of which guide,pins. fit into the counterbored ends of theopenings 42 in the die element 22. r

The die elements. and 32 are resiliently held together under highpressure against the end wall 28 by means comprising a rubber pad 44,which is of substantially the same area as the outside wall of the dieelement 22, and disposed within the opening 31 of the housing 30. Apressure equalizer plate arranged within the opening 2! is provided withshoulders 48 which form, with the-side walls of the housing 30, a largerecess 41 for receiving the rubber pad 44 on one side of the plate. Theopposite side of the plate 45 is provided with a plurality of smallrecesses 48 to receive the ends of pressure adjusting screws 48 whichextend inwardly into the opening 31 through openings 50 in the end wall5| of the housing 90. By providing the plate 45, the pressure of thescrews 49 thereon is uniformly distributed over the rubber pad 44 whichcontacts the outside wall. of the die element 22 and causes the same tobe resiliently held together with the die element 3|.

The powdered material may be fed to the die D in any suitable manner,and as shown in Figs. 1 and 5 is fed by gravity from a hopper, 52 havingthe outlet opening at the bottom thereof connected to the upper end of aconduit 52, the lower end of which is connected at a boss 54 tocommunicate with an aperture 55 formed in the upper side wall of thehousing 30. The aperture 55 is in direct alignment with an aperture 58which is formed by cooperating grooves in the upper parts of the dieelements 3| and 32, so that the powdered material may flow into the dieopening 21 intermediate its ends. When it is desired to formautomatically a rod composed of a mixture of powdered materials, thehopper 52 may be provided with an agitator and form a main hopper intowhich may be fed different powdered materials from several otherhoppers.

The powdered material is compacted and compressed in the die D andextruded therefrom in the form of the rod 29. The rod 29 passes throughguide rolls 5'! supported on spaced blocks 58, which are mounted on andinsulated from the frame II at 59. The guide rolls 5'! are pro;- videdto prevent any bending of the rod 29 between the die D and an electricalcontact E through which the rod 29 passes.

As shown in Figs. 1 and 3, the contact E may comprise a pair of contactshoes 60 having cooperating longitudinal grooves which form an opening6| to accommodate the rod 29. Each of the shoes 80 is provided withguide pins 62, which pass through openings 83 in blocks 64 that aremounted on and insulated from the frame I! at 95. The shoes 60 areguided by the pins 82, and, in order to obtain good electrical contact,they may be slightly and firmly pressed against the rod 29 by helicalsprings'66 attached at one end to the backs of the shoes 60. The tensionof the springs 66 may be adjusted by threaded studs 61 that extendthrough openings 68 in the blocks 85, the ends of which studs havebearing surfaces 69 to contact the free ends of the springs. The shoes60 may be hollow and provided with inlet and outlet openings 18 and Hfor circulating a cooling medium therethrough to dissipate the heat theshoes receive as a result of heating the rod 29, to be described.

An electrical conductor 12 connected to one terminal of a source ofsupply of electrical energy, not shown, is connected at 13 to the shoes68. The opposite terminal of the source of supply is connected by aconductor 14 to the upper end of the frame I! at 15, thereby completingan electrical circuit for passing a current through a portion of the rod29 to heat the same progressively as-it is extruded from the die. Theelectrical circuit formed comprises one terminal of the source ofsupply, conductor 12, contact E, the portion of the rod 29 extendingbetween the contact E and the die D, the die D, the frame l7; andconductor M back to the opposite terminal of the source of supply.

By introducing a current of sufficient magnitude in the rod 29 in thismanner, the current preferably being an alternating current, the

bonding of the particles of the comminuted material may be increased bysintering or semifusion. Moreover, the heating of the rod 29 may driveoff any undesirable volatile matter in the material. Y

In order to insure the production of a rod having substantially constantphysical properties, it is desirable to heat successive portions of therod to a predetermined value of temperature. For this purpose, means maybe provided to con trol the rate at which the rod 29 is extruded fromthe die D as the temperature of the rod varies froma predeterminedtemperature.

As shown in Fig. l, I prefer to use a photoelectric apparatus Ccomprising a photoelectric cell 175', which may be focused on the heatedrod 25 in any suitable manner, as by a lens 16 positioned in a tube 11.This apparatus may be mounted in any suitable manner on one side of theconduit 53. The cell 15' is responsive to changes in the radiant energyemitted by the heated rod 29, and may be connected to controlautomatically the speed of the driving motor M which actuates theplunger 25 of the die D.

Referring to Fig. 6, this may be accomplished by connecting thephotoelectric cell 15 by conductors l8 and 19 to the input terminals ofa suitable amplifying unit A, which may have a fiament-current supplyconnection 80 and an amplification control knob 8|. The circuit 82 ofthe amplifying unit A includes a conductor 83 that is connected througha switch 84 to one side of the main supply circuit 85 to which isconnected, by conductors 86 and 81, the armature 88 of the driving motorM. The conductor 89 of the circuit 82 is connected through the fieldwinding 98 of the motor M and variable resistor 9i to the opposite side"of the main supply circuit 85.

This photoelectric cell 15' reacts to changes in the radiant energyemitted by the heated rod 29 to efiect changes in the value of currentflowing in the input circuit 19. The amplifying unit A, with suchchanges of current in the input circuit 19, varies, in a well knownmanner, the value of current in the circuit 82 to change the fieldexcitation producedby the field winding 98. This changes the speed ofthe motor M to increase or decrease the rate of reciprocation of. theplunger 25, and thus extrude the rod 29 faster or slower from the die D.

In order to start producing a rod of comminuted material, the motor' Mis rotated until the plunger 25 is at the end of a compression stroke,as indicated in dotted lines in Fig. 2. The upper end of the die opening21 is then filled with compacted comminuted material. This may be doneby alternately pouring comminuted material and compacting the same, bymeans of a ramrod, until the frictional resistance between the walls ofthe die opening 21 and the section of compressed material thus formedapproximates the frictional resistance of the compressed material whenit is formed during normal operation of the apparatus.

The operation of the above described apparatus is substantially asfollows: It will be assumed that the upper end of the die opening 21 hasbeen filled with compacted powdered material, as described above; thatthe hopper 52 is-filled with the powdered material; that the conductorsl2 and 14 are connected to a source of electrical energy which willdeliver approximately constant current; that the switch 84 in thecircuit 82 is in closed position; that the supply lines 85 are energizedto drive the motor M; and that the photoelectric apparatus C istemporarily rendered inoperative.

With the above assumed conditions, the motor M will drive the shaft l4through the shaft I0, coupling [2, shaft l3, and reduction gearing inthe housing l5, and impart a rectilinear reciprocatory motion to theplunger 25 through the thrust rod 23 and connecting rod I9.

When the plunger 25 is at the beginning of a compression stroke, asshown in solid lines in Fig. 2, a predetermined quantity of the powderedmaterial will flow by gravity from the hopper 52 through the conduit 53,aperture 55 and aperture 56, and occupy the space 82 in the die opening27, between the lower end of the aperture 55 and the impacting end 28 ofthe plunger 25. At the beginningof the compression stroke of-the plunger25, the powdered material in the space 92 is merely forced upward.Compacting of this material does not begin-until the impacting end 28 ofthe plunger 25 has passed the aperture 56. By delaying the compacting ofthe material in the space 92 until the plunger 25 has closed the lowerend of the aperture 56, this material is prevented from being forcedback intothe aperture 56 again. Stated another way, ,until the impactingend 28 of the plunger 25 moves past the aperture 56, there will alwaysbe a space in the die opening 21 between the lower end of the materialpreviously compressed and the quantity of loose material being forcedupward by the plunger 25.

After the plunger 25 has closed the lower end of the aperture 58, thequantity of loose material moved upward is forced against the previouslycompressed material. During the remainder of the compression stroke ofthe plunger 25, the quantity of loose material in the space 92 is compacted and compressed with the material previously compressed, and anincrement of the rod thus formed is extruded from the die opening 21.

The return stroke of the plunger 25 then takes place, and anotherpredetermined quantity of powdered material fills the space 92 in thedie opening 21, between the lower end of the aperture 59 and theimpacting end 29 of the plunger 25. This quantity of materialisthenmoved u ward in the die opening 21 by the plunger 2 and compactedand compressed with the material compressed during the previouscompression stroke of the plunger.

Compacting and compressing oi the powdered material is obtained in thismanner because of the frictional resistance between the walls'oi the dieopening 21 and the compressed material. The density of the compressedmaterial may be readily controlled by the pressure adjusting screws 49that maintain the die elements 3i and 92 together. When the die elements3| and 92 separate to relieve the radial pressure'of the compactedmaterial and permit the same to move through the die opening 21, theseparation is so slight that partlcles of powdered material cannot flowinto the spaces between the die elements and tend to cause them toremain separated after the radial pressure is relieved.

The extruded rod passes between the guide rollers 51, and through theopening N of the contact E. This completes an electric circuit betweenthe conductors I2 and 14, so that an electric current will flow throughthe rod 29 between the die D and contact E, as described above, to heatthe same and increase the cohesion orebonding of the powdered material,and to drive 01! any volatile vapor matter that may be present in thematerial.

The electric current supplied to the conductors l2 and M is preferablyfrom a source of approximately constant current. After the heated rod 29has reached a predetermined normal value of temperature, thephotoelectric cell 15 is then rendered operative. When the heated rod291s at the predetermined value of temperature, the value of currentflowing in the field winding 99, and hence the speed of the motor M, aresubstantially at normal. Any variation of the'heated rod 29 from thepredetermined value of temperature ,produces a corresponding change inthe amount of radiant energy that reaches the photoelectric cell 15.This produces a change in the value of the motor M. The change in motorspeed varies the rate of compacting the predetermined quantitlesofpowdered material by the plunger 25,

thereby tending to reestablish the predetermined value of temperature ofthe heated'rod 29.

Thus, when the temperature of the heated rod 29 becomes higher than thepredetermined normal value of temperature, the radiant energy emitted bythe rod 29 increases and eflects,

through the photoelectric cell 15' and amplifying unit A, a decrease inthe value of current flowing in the field winding 90. Lowering the valueof field excitation increases the speed of the motor -M, therebyextruding the rod 29 faster from the in the field winding 90. Raisingthe value of field excitation decreases the speed of the motor 'M,thereby extruding the rod 29 slower from the cooling of the rod, acooling medium, such as a Jet of atr, may be applied to the rod as itpasses from the contact E. For producing rods of uniform length,automatic means may be provided to cut the extruded rod at definiteintervals of time. Since the rate of extrusion of the rod from the die Dmay vary, it will be desirable to provide cutting means which will varywith the rate the rod is produced. This may be accomplished by providinga rotatable burner which is adapted to out the rod when the flameproduced thereby passes over the rod. The burner may be mounted on ahollow rotatable spindle supplied with a suitable combustible gas, andthe speed of rotation of the spindle may be arranged to be responsive tothe rate of extrusion of the rod 29, as by driving the same from themotor M.

In Figs. 7 to 9, I have shown a modification of the apparatusillustrated in Figs. 1 to for produclng hollow or tubular rods ofcomminuted In this embodiment of my invention,

material. the parts of the apparatus, hereinafter to be described, aremounted on a frame 11 which is preferably extended vertically. This maybe accomplished by mounting the frame H on a base plate similar to thebase plate I i shown in Fig. 1, and providing suitable brace memberssecured to the base plate and frame II, respectively. In Fig. 7, theupper end of one such brace member I8 is shown secured at l9 to the.frame l'l.

Apparatus similar to that shown in Fig. 1 may be provided to impart arectilinear reciprocatory motion to a thrust rod 23', which reciprocatesin a guide block 24' that is mounted on the frame H. The end of thethrust rod 29 is recessed and internally threaded at 29' to receive theexternally threaded outer end of a hollow plunger 25'. The plunger 25'reciprocates in an opening 21' of a die-D, which is mounted on the frameH. The impacting end 29' of the plunger 25 is notched or castellated, asclearly shown in Fig. 9, so as to insure a strong Joint betweensuccessive quantities of powdered material as they are compacted andcompressed together by the plunger 25' to form the hollow rod 29'.

, The die D' is a split die similar to the one shown in Figs. 4 and 5,described above, and comprises 9. housing 99' having an opening in whichare positioned cooperating die elements resiliently held together underpressure, one of which is indicated at 32 in Figs. '7 and 9. The dieelements are provided with cooperating longitudinal grooves, which maybe nitrided or lined at 34' with a hard metal to form the die opening27'.

In order to provide a rigid structure, a thrust plate 3i, having anopening Sia in alignment with the die opening 21', may be secured bybolts 9!!) to the frame i'I' adjacent the upper end of the die D.

The powdered material may be fed from hoppers (not shown) which areconnected to conduits 53', the lower ends of which are connected atbosses 94" to communicate with a. plurality of apertures which areformed in the side walls of the housing 80'. As indicated at in Fig. 7.two such apertures are shown. The frame I1 is provided with an openingIla, through which the left hand boss 64' projects. The apertures 65'are in direct alignment with apertures 00', which are formed bycooperating grooves on the contacting faces of the die elements 82'. Theapertures 56' communicate with the die opening 21', intermediate theends thereof, and are disposed at diametrically opposite points of thedie opening.

In order to produce hollow or tubular rods of comminuted material, amandrel 98 is centrally disposed in the die opening 21' and extendssubstantially the length thereof. The mandrel 90 may be made integralwith the hollow plunger 25' and reciprocate therewith, or may be fixedlysecured in a suitable manner, so as to remain stationary with respect tothe reciprocating hollow plunger 25'. As shown, the mandrel 93 extendsthrough the hollow plunger 25' and an opening 23a at the end of thethrust-rod 28', and the lower end thereof is fixedly secured to theguide block 24'. This may be accomplished by making the guide block 24 asplit block, and having the respective halves 94 thereof provided withco-operating longitudinal grooves 90 to form an opening in which thethrust rod 23' reciprocates.

As shown in Fig. 8, each half 94 of the guide block 24' is transverselyrecessed at 96. When the two halves 94 of the guide block 24' aresecured together and mounted on the frame I'I' by cap screws 97, therecesses 96 cooperate to form a transverse opening which receives a bar98.

As shown in Fig. 7, the bar 98 extends through a longitudinal slot 99inthe thrust rod- 23', so that the latter is free to move up and down inthe guide block 24' and impart a reciprocatory motion to the plunger25'.

The lower reduced end of the mandrel 93 extends through a centralopening I00 in the bar 98, and in this manner is shouldered at IOIagainst the upper side of the bar 98 so that downward movement thereofis prevented. Upward movement of the mandrel 93 is prevented .by keyingthe same at I02 against the lower side of the bar 98. By thisconstruction, longitudinal movement of the mandrel 991s prevented, thethrust rod 23' freely reciprocates in the guide block 24', and thehollow plunger 25' freely reciprocates in the'die opening 21' and slidesup and down along the mandrel 93.

Guide rolls, an electrical contact, connections to a source of supply ofelectrical energy, and apparatus for controlling the rate of compactingand compressing of powdered material may be provided in the same manneras illustrated in Figs. 1 to 6, and described above.

The operation of the apparatus just described for producing hollow rodsis substantially the same as the first dcscribed'embodiment of myinvention:

In order to start producing hollow rods, the plunger 25 is moved to theend of a compression s roke, indicated in dotted lines in Fig. 9, andthe upper end of the die opening 21' is filled with compacted powderedmaterial. The motor for reciprocating the plunger 25 is then connectedto the supply lines.

When the plunger is at the beginning of a compression stroke, asindicated in solid lines in Fig. 9, a predetermined quantity of powderedmaterial will flow through the apertures 56' and occupy the space 92' inthe die opening 21'. By

providing two apertures 50', a uniform distribu-' vention, compactingand compressing does not v.begin until the plunger 25' has moved pastthe apertures 60', thereby insuring complete compaction of eachpredetermined quantity of powdered material that fiows by gravity intothe space 92'.

After the plunger 20' has closed the lower end of the apertures 08'during a compression stroke, the powdered material is compacted andcompressed with the material previously compressed, and an increment ofthe hollow rod 29 thus formed is extruded from the die opening 21".Heating of successive portions of the rod 29 and varying of the rate ofproducing the rod to obtain substantially uniform heating may beaccomplished in the same manner as in the first described embodiment ofthis invention.

In Fig. I have illustrated apparatus for progressively fusing or meltingsuccessive portions of a rod after they are extruded from a die, and forsubsequently cooling such fused portions,

Since many of the parts of this apparatus are similar to those describedabove and illustrated in Figs. 1 to 5 inclusive, only the essentialdifferences will be pointed out for a complete understanding of thisembodiment of my invention.

In this modification a plate III is mounted vertically on a base plateIII, and provided with one or more brace members I I8. Apparatus similarto that shown in Fig. 1 is provided for imparting a rectilinearreciprocatory motion to a plunger I25 for compacting comminuted materialin the form of a rod I29 and extruding the same from a split die D" intoa tube T of refractory material, such as alundum or carborundum. Incases where carburization of the material fused is not objectionable,graphite may be employed as the refractory material. This tube T extendsbetween the upper end of the die D" and the lower end of the electricalcontact E", and its bore I03 is substantially the same size as that ofthe rod I29.

In order to maintain the tube T in alignment with the opening I21 in thesplit die D" and the opening IBI in the contact E", each of the dieelements I32 and the shoes I64 of the contact E" are provided withflanges I04 and I05 of semicircular shape for gripping the upper andlower ends, respectively, of the refractory tube T. The contact E" issimilar to the contact E described above and clearly shown in Fig. 3,with helical springs for firmly holding the shoes I64 together. Becauseof this construction of the contact E", the flanges I05 on the shoes I64will also firmly hold the upper end of the refractory tube T inalignmentwith the opening I6I in the contact E". The lower end of the tube Trests firmly on the upper end of the die elements I32, and lateralmovement thereof is prevented by the flanges I04.

The electrical circuit for progressively heating successive portions ofthe rod I29 comprises an electrical conductor I12 which is connected toone terminal of a source of supply of electrical energy, contact E", theportion of the rod I29 extending between the contact E" and the die D",the die D", the plate Ill, and .conductor I'I4, which is connected tothe opposite terminal of the source of supply.

Although the apparatus Just described may be employed where it isdesired to introduce a cur- .rent of such magnitude that the particlesof metals and alloys, such asbrasses and bronzes,

is refined and improved by-such quick freezing. For producing such rodsof an improved and re- .flned' nature: the operation of the apparatusdescribed is substantially as follows:

The feeding. of the comminuted material into the 'die'opening I21, thecompacting and compressing of the material into the form of sand,

and the extrusion thereof from the diet)" are the same as in thepreviously .described embodiments of my invention, and will thereforenot be repeated here. After the rod I20 has moved past the electricalcontact E",'the electric circuit is completed between the conductors I12and I",

and an electric current will fiow through. the material between theupper end of the die D and the electrical contact E". rent is of suchmagnitude that the comminuted material is heated to its fusingtemperature.

The comminuted material will not completely fuse until it has movedupward a slight distance from the bottom ofthe refractory tube T. Thus,

the compacted comminuted material is still in its solid'form as itenters the lower end of the tube T, and fused material I20 above itcannot fiow I from the tube T and into the space between the tube andthe flanges I04 of the die'elements I32. If it becomes necessary to coolthe die elements,

they may be provided with longitudinal openings I through which acooling medium or refrigerant can be circulated- As the fused materialI20'- in the tube T is moved upward and approaches the bottom of theelectric contact E" by the continuous reciprocation of the plunger I25,the material freezes quickly. This is due to the cooling of the contactE" by circulating a cooling medium or re-' frigerant through the hollowshoes IN.

The temperature and circulation of the cooling medium or refrigerant canbe so controlled that as the fused rod nears the contact E", heat israpidly conducted along and from the rod so that the rod is solidifiedwhen it enters the opening IBI of the contact E". In this manner anytendency of the fused material to leak from the tube fI' into the spacebetween the tube and the flanges I05 of the contact E" is prevented.

Although I have illustrated the passing of an electric current through arod to heat the same,

such heating may be accomplished by introducing or inducing a highfrequency current in the rod. The rod may also be heated in other ways,

as by hot gases directed and confined about the rod as it is extrudedfrom the die; or by a furnace, such as a small electric furnace,disposed about the rod in any suitable manner. With substances thatcombine with a strongly exothermic reaction, such as a mixture ofchromium and 15% aluminum,-a portion or all of the heat required forheating the material may be supplied by such a reaction. Thus, with theapps,- ratus illustrated and described, current of a sufficientmagnitude may be passed through the compressed material to raise thesame to a temperature at which the reaction will start. After such anexothermic reaction begins, all of the heat re- The electric curpowderedmaterial.

quired for fusing the material may be supplied by the reaction, orsuchheating maybe utilized in conjunction with the heating produced by theelectric current. V

In'makingrods of powdered metals, it has been found that the ohmicheating, as above described, heats the rods formed so rapidly'that verylittle oxidation of themetailic particles takes place.

Where it is desired to produce a rod having a bright finish, or toprotect a product that'oxidizes readily, it may be necessary to arrangeall or a portion of the apparatus in an enclosure through which anon-oxidizing'gas, such as hydrogen'or carbonmonoxide, may becirculated. In certain applications, it may be des'irableto evacuatesuch an enclosure to minimize the trapping of air in the compactedmaterial, and thereby increase the density of duced.

In the apparatusillustrated in Fig. 10, this is accomplished byproviding a housing I00 which may be secured, as by welding, to theplateIII so as to enclose the die D", refractory tube T and electriccontact E". In order to provide an airtight enclosure,.the guide blockI24, which extends through an opening at the lower end of'the' I housingI08, may be provided with packing'mathrust rod I 23 by a packing glandI01. Likewise, a guide block I08 mounted on the plate III I andextending through an opening at the upper the rods pro- I terial I01which is retained in position about the material I08 which is retainedin position about 1 the rod I20 by a packing gland I00 The openinghousing I00- die opening I21, extends through an opening I I06 in thehousing I06. The'hopper I 52 is maintained air-tight by a hinged coverI52a' having a gasket I52?) and a screw and clamping nut I520.

The conduits I'I0 a and IIIa for circulating a cooling medium throughthe hollow shoes I64 extend through insulating bushings H01) and III?)in the wall of the housing I08. In a similar manner, the electricconductor I12 is connected to one terminal of the source of supply ofelectric energy through an insulating connection II2a in the wall of thehousing I08.

With the above described construction, an airtight enclosure is providedwhich may be evacuated by a pump connected by a conduit I06a to thehousing I00; or filled with a non-oxidizing gas from a suitable sourceof supply through a conduit I00b connected to conduit I 00a. Inoperating the apparatus illustrated in Fig. 10 when the material isfused in the refractory tube T. it may be desirable to purge the housingwith a gas, such as hydrogen, and then evacuate the housing. Byevacuating the housing, all of the occluded gases in the compressedmaterial are drawn out so that dense homogeneous rods are produced.

In preparing comminuted material for producing rods, it may be desirablein some cases to employ a temporary fugitive constituent in the Thisconstituent may be of such a nature as to provide temporary adhesion ofthe particles until they are finally bonded, as by sintering; or toprovide a lubricating efiect for the sliding of the compacted andcompressed material through a die; or, in some instances, to give bothof the above mentioned actions.

The. conduit in, through which comminuted materialtis fed from thehopper I52 and into the quantities of said comminuted material by ram-This adhesive or lubricative constituent preferably should be of such anature that it may be driven oil? by decomposition or vaporization whenthe rod is heated. Dry soaps, such as zinc stearate, possess excellentlubricating properties, and in powdered form may be readily mixed withpowders of metals. It has been found that as little as 0.25% of zincstearate produces sufficient lubrication in a mixture of copper, tin andnickel powders, and that the zinc stearate leaves no ob- Jectionableresidue, inthe rod formed of the above materials, after it has beensintered.

The temporary constituent added may be a substance of a viscous type.such as a soap; or it may be of a type which is corrosive in its action,so as to form metallic compounds that bridge between all or a portion ofthe particles. and subsequently harden. as a matrix. Chemical binderswhich have been found suitable for this purpose are phosphoricanhydride, sulphuric acid, and chromic anhydride. Certain temporarybinders, such as phosphoric anhydride, readily mix with metallic powderswhile in a dry state. After mixing such binders with the powderedmaterial, sufficient moisture is absorbed from the ,air to produce acorrosive action on the particles of comminuted metal.

It is to be understood that in the claims which follow, the term "rod"broadly includes solid rods, hollow or tubular rods, and wires andthelike.

While I have shown and described particular embodiments of my invention,it will be obvious to those skilled in the art that modifications mav bemade, and that certain features may be used independently of otherswithout departing from the spirit and scope of my invention.

I claim:

l. The method of producing rods uncomminuted material includingsubstances which combine with an exothermic reaction. which comprisescompressing the material into the form of a rod; progressively heatingsuccessive porti ns of the rod to a fusing temperature after, it isformed; at least a portion of such heat being supplied by the exothermicreaction of the comminuted substances; and thereafter progressivelycooling the heated portions of the rod below their fusing temperature.

2. The method of producing rods which comprises compacting predeterminedquantities of comminuted material including comminuted metals which'combine with an exothermic reaction; compressing each added quantity ofcompacted material against the material previously compacted so as toform a rod of the compacted material; progressively heating successiveportions of the rod to a fusing temperature after it is formed; at leasta portion of such heat being supplied by the exothermic reaction of thecomminuted metals; andthereafter progressively cool- 7 ming each suchsuccessive quantity against the next preceding compressed and shapedquantity thereof whereby to form a continuous rod of said-material, andpassing the rod, immediately as formed. into and through a heated zonewherein the continuous rod is progressively heated to a temperature atwhich an at least partial bonding of the particles of comminutedmaterial-in the continuous rod occurs.

5. The -continuous method of producing a rod which comprises mixing alubricant with comminuted material to reduce the coefllcient of frictionbetween said material and an elongated die having an open end;successively compacting predetermined quantities of said lubricatedmaterial in said die against the'quantity of material previouslycompacted; pushing the compacted material through the open end of saiddie; and heating the rod after it is formed so as to drive oil suchlubricant.

6. The method of producing rods of comminuted material which comprisessubstantially continuously compacting and compressing comminutedmaterial so as to form a rod of the compacted material; progressivelyheating to a predetermined temperature successive portions of the red asthey are formed; and varying the rate of forming the rod in accordancewith variations in the heated condition of .the rod from thepredetermined temperature.

'7. The method of producing rods of comminuted material which comprisescompacting predetermined quantities of the comminuted material andcompressing each added quantity of compacted material against thematerial previously compacted so as to form a rod of the compactedmaterial; progressively heating ap proximately to a predetermined valueof temperature successive portions of the red as they are formed; andvarying the rate of compacting the predetermined quantities of thecomminuted material as the temperature of the heated portions of the rodchanges from the predetermined value, such variations in the rate ofcompacting the predetermined quantities of material being responsive tosuch temperature'changes and tending to reestablish such predeterminedvalue of temperature.

8. The method of producing rods of comminuted material which comprisescompacting predetermined quantities of the comminuted material andcompressing each added quantity of compacted material against thematerial previously compacted so as to form a rod of the compactedmaterial: progressively heating approx mately to a predeterminedtemperature successive portions of the rod as they are formed so astobond together the particles of comminuted material; and varying therate of compacting the predetermined quantities of the comminutedmaterial in accordance with changes in radiant energy emitted by suchheated portions of the rod.

9. Apparatus for producing rods of comminuted material in powdered formwhich comprises the combination of a die having an opening, means forprovdng a cont nuous supply of the material'to the opening of said die;means for intermittcntly compressing successive predetermined quantitiesof the material in the opening of said die and for extruding thecompressed material from said die in the form of a continuous rod; saidcompressing means including a reciprocatory plunger movable in theopening of said die and adapted to compress with each compressive strokea predetermined quantity of material in the opening of saiddie againstthe material previouslyicompacted; a refractory conduit having anopening aligned with said die opening to continuously receive said rodas it is extruded from said-die; and means for progressively heatingsuccessive portions of the rod as they pass through said refractoryconduit.

10. Apparatus according to claim 9,-in which said die and said heatingmeans are-arranged in an enclosed housing; and means for evacuating saidhousing.

lLApparatus for producing rods from comminuted material in powderedform, which comprises the combination of a die; means for feeding thematerial into said die; means for compressing the material in said dieand extruding the compressed material substantially continuouslytherefrom in the form of a rod; and means I for progressively heatingsuccessive portions of the rod as they are extruded from said die; saidlast mentioned means comprising an electric circuit which includes thesaid die, a pair of coopcrating grooved contact shoes and the portion ofthe extruded rod lying between the said die and contact shoes; andyielding means operatively associated with the said shoes and adapted tourge the latter into contact with each other and with the said rod.

12. Apparatus for producing rods of comminuted material comprising thecombination of a split die including cooperating die elements providedwith cooperating grooves to form a die opening adapted to receive aplunger, and means for holding said die elements together underpressure; said last-mentioned means including resilient means to provideradial relief for said cooperating die element when the material tendsto jam in said die opening.

13. Apparatus for producing rods of comminuted material comprising thecombination of a split die, the respective elements of which die areprovided with cooperating longitudinal grooves at their contacting facesto form a die opening adapted to receive a plunger, and means includingat least one rubber pad for resiliently holding said die elementstogether underpressure.

14. Apparatus for producing rods and the like of comminuted materialincluding the combination of a housing having an opening, a split diepositioned within said opening and comprising a plurality of cooperatingdie elements provided with cooperating grooves to form a die opening,and means positionedin the opening in said housing for resilientlyholding said die elements together under pressure.

15. Apparatus for producing rods of comminuted material comprising thecombination of a die having an opening, a material compacting plungeradapted to be received in the die opening and having a bore, a mandreldisposed in the die opening and extending through the bore of saidplunger, said plunger having the impacting end thereof notched, andmeans for intermittently reciprocating said plunger in said die.

16. Apparatus for producing rods of comminuted material comprising thecombination of a split die including cooperating die elements providedwith cooperating grooves to form a die opening adapted to receive aplunger, and means for resiliently holding said die elements togetherunder pressure, at least one of said die elements having an aperturecommunicating with the die opening at a point intermediate the endsthereof for introducing the comminuted material into the die opening.

17. Apparatus for producing rods of comminuted material comprising thecombination of a support; a split die mounted on said support; suchsplit die including cooperating grooves to form a die opening in asubstantially vertical plane; means for resiliently holding said dieelements together under pressure; a plunger adapted to be received atthe lower end of the die opening; and means for imparting a rectilinearreciprocatory motion to said plunger in the die opening; at least one ofsaid die elements having an aperture for introducing the material bygravity into the die opening; such aperture being disposed above theimpacting end of said plunger when the latteris at the beginning of acompression stroke.

18. Apparatus for producing rods of comminuted material, whichcomprisesthe combination of a die; means for feeding the material intosaid die, means for compressing the material in said die and extrudingthe compressed material substantially continuously therefrom in the formof a rod; means for progressively heating successive portions of the rodas theyare extruded from the die; and means responsive to the heatedcondition of the rod for controlling the quantityv of heat applied tosuch successive portions of the tion of a die; means for compressing thematerial in said die and extruding the compressed material substantiallycontinuously therefrom in the form of a rod means for progressivelyheating successive portions of the rod as they are extruded from thedie; and means responsive to the heated condition 0! the rod forcontrolling the rate at which the rod is extruded from said die.

20. Apparatus according to claim 19, in which said means for controllingthe rate at which the rod is extruded from said die comprises a devicesensitive to variations in radiant energy emitted by the heated portionof the rod.

21. Apparatus for producing rods of comminuted material which comprisesthe combination of a die having an opening; a plunger adapted to bereceived in the die opening; means for feeding predetermined quantitiesof the material into the die opening; means for operating said plungerto exert a high pressure to compact intermittently the predeterminedquantities of the material, to compress each quantity of compactedmaterial against the quantity of material pre-

